Causal agent of bacterial rot of onion (Allium cepa) bulbs in the Tohoku region of Japan

Abstract

For identifying the causal agent of bacterial rot of onion (Allium cepa L.) bulbs cultivated for a new cropping type for summer harvest in the Tohoku region, bacteria were isolated from symptomatic plants at different stages. Pseudomonas marginalis, Pantoea ananatis and Erwinia rhapontici were isolated from onion leaves cultivated in the region, and Burkholderia cepacia was mainly isolated from rotted bulbs at harvest or after. Pathogenicity tests suggested that the rot disease of onion bulbs during storage in the Tohoku region was caused by B. cepacia, which may invade plants before harvest and cause disease later.